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AnnotatedElement getDeclaredAnnotationsByType() method in Java with Examples
  • Last Updated : 03 Jan, 2020

The getDeclaredAnnotations() method of java.lang.AnnotatedElement class is used to get the declared annotations of the specified declared annotation type present in the class implementing this interface. The method returns an array of declared annotations for the specified declared annotation type.

Syntax:

public A[] getDeclaredAnnotationsByType(Class<T> declared annotationClass)

Parameter: This method accepts a parameter declared annotationClass which is the type of the declared annotation to get.

Return Value: This method returns an array of declared annotations for the specified declared annotation type.

Exception: This method throws:



  • NullPointerException: if the given declared annotation class is null.

Below programs demonstrate the getDeclaredAnnotationsByType() method.

Example 1:




// Java program to demonstrate
// getDeclaredAnnotationsByType() method
  
import java.util.*;
import java.lang.reflect.*;
import java.lang.annotation.*;
  
// create a custom DeclaredAnnotation
@Retention(RetentionPolicy.RUNTIME)
@interface DeclaredAnnotation {
  
    // This declared annotation has two attributes.
    public String key();
  
    public String value();
}
  
// call DeclaredAnnotation for method
// and pass values for declared annotation
@DeclaredAnnotation(key = "GFG", value = "GeeksForGeeks")
public class Test {
  
    public Object obj;
  
    public static void main(String[] args)
        throws ClassNotFoundException
    {
  
        // returns the Class object
        // for this myAnnotatedElement
        AnnotatedElement myAnnotatedElement
            = Test.class;
  
        System.out.println(
            "AnnotatedElement represented"
            + " by myAnnotatedElement: "
            + myAnnotatedElement.toString());
  
        // Get the declared annotation
        // using getDeclaredAnnotationsByType() method
        System.out.println(
            "DeclaredAnnotation of myAnnotatedElement"
            + " of type DeclaredAnnotation: "
            + Arrays.toString(
                  myAnnotatedElement
                      .getDeclaredAnnotationsByType(
                          DeclaredAnnotation.class)));
    }
}
Output:

AnnotatedElement represented by myAnnotatedElement: class Test
DeclaredAnnotation of myAnnotatedElement of type DeclaredAnnotation: [@DeclaredAnnotation(key=GFG, value=GeeksForGeeks)]

Example 2:




// Java program to demonstrate
// getDeclaredAnnotationsByType() method
  
import java.util.*;
import java.lang.reflect.*;
import java.lang.annotation.*;
  
@Deprecated
public class Test {
  
    public Object obj;
  
    public static void main(String[] args)
        throws ClassNotFoundException
    {
        try {
  
            // returns the Class object
            // for this myAnnotatedElement
            AnnotatedElement myAnnotatedElement
                = Test.class;
  
            System.out.println(
                "AnnotatedElement represented"
                + " by myAnnotatedElement: "
                + myAnnotatedElement.toString());
  
            // Get the declared annotation
            // using getDeclaredAnnotationsByType() method
            System.out.println(
                "DeclaredAnnotation of myAnnotatedElement"
                + " of type Deprecated: "
                + Arrays.toString(
                      myAnnotatedElement
                          .getDeclaredAnnotationsByType(
                              Deprecated.class)));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}
Output:

AnnotatedElement represented by myAnnotatedElement: class Test
DeclaredAnnotation of myAnnotatedElement of type Deprecated: [@java.lang.Deprecated()]

Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/reflect/AnnotatedElement.html#getAnnotationsByType-java.lang.Class-

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